"$US6 billion is a very low cost for getting people to Mars and sustaining them there," he said.

"The other problem is of course they want to raise this money through some sort of reality TV venture, and as we know reality TV ventures come and go and people are one minute interested and the next minute they couldn't care less.

"So what happens when it gets to the stage when the viewers can't care less and the funding dries up?"

He, like many others, also question the ethical implications of the project.

"I personally think that sending anyone off on any sort of expedition with no chance of coming home is not right," he said.

Mars One CEO Bas Lansdorp says a new group of volunteer astronauts will make the seven-month journey to Mars every two years after the first crew departs in 2022.

We will select people and we will tell those people the risk and they will have to weigh the risks. [To say] 'do I want to take these risks to make my dream come true or do I not?'.

Bas Lansdorp, Mars One CEO

"When you send people to Mars there will be risks," he said.

"But we will select people and we will tell those people the risk and they will have to weigh the risks.

"[To say] 'do I want to take these risks to make my dream come true or do I not?'."